In Section 8.1.1 <http://www.w3.org/TR/html5/syntax.html#the-doctype>., the
current published specification says:
A DOCTYPE is a mostly useless, but required, header.
It then goes on to say:
DOCTYPEs are required for legacy reasons. When omitted, browsers tend to use
> a different rendering mode that is incompatible with some specifications.
So, not useless then, or even mostly useless, as it's required to ensure
that the most common UAs in the world (web browsers) behave something close
to properly.
Perhaps consider dropping the "mostly useless" comment to avoid encouraging
skimmers to drop it. Perhaps "A DOCTYPE is a required header that primarily
serves a legacy, but significant, purpose."
(Separately: It's a header? That seems an odd term for it.)
Regards,
--
T.J. Crowder
tj @ crowdersoftware / com
www / crowder software / com